Allergic rhinitis, atopic dermatitis and asthma are three clinical disorders which are grouped under the name "atopy," a Greek word meaning "altered reactivity." These clinical disorders tend to occur together within a single individual. In addition, these disorders tend to cluster within families, and family members might be affected with one or more manifestations with varying degrees of severity.
According to one hypothesis, the unifying feature which underlies the atopic disorders is an altered reactivity or, more specifically, a lack of responsiveness to adrenergic (adrenalin-like) stimulation. (Szentivanyi A. The beta adrenergic theory of the atopic abnormality in bronchial asthma. J. Allergy 42:203-232, 1968.) Responsiveness to adrenergic stimulation may be measured by the effect of administering an adrenergic stimulant. Adrenergic stimulants are compositions characterized by their ability to produce effects similar to the effects produced by the administration of adrenalin. Adrenergic stimulants include medications such as adrenalin, isoproterenol, and albuteral.
When an adrenergic stimulant is administered to individuals with atopy, the effect on widely divergent organ systems is blunted compared to the effect in non-atopic individuals. For example, when an adrenergic stimulant is administered to atopic individuals, it produces less of a rise in blood sugar, less of an effect on peripheral white blood cells and less of an effect on bronchial smooth muscle than in non-atopic individuals. This condition is referred to as adrenergic blockade. Adrenergically blockaded conditions (AdBCs) include the following: respiratory allergies, skin allergies, and asthma.
A relationship between steroidogenesis and adrenergic blockade, the basic pathophysiologic abnormality associated with atopic disorders, has been previously unrecognized. Researchers, however, have recently found that the diminished adrenergic responsiveness in individuals with AdBCs results in a decrease in steroidogenesis. (Weinstein R E, Lobocki C A, Gravett S, Hum H, Negrich R, Herbst J, Greenberg D, Pieper D R. Decreased adrenal sex steroid levels in the absence of glucocorticoid suppression in postmenopausal women. J All Clin Immunol 97:1-8, 1996.) Serum levels of the sex steroids, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), and estrogens have been found to be decreased in AdBCs. This finding resulted from a study of asthmatic women, who are representative of subjects with AdBCs in that the bronchial response to adrenalin is found to be altered in these individuals. (Szentivanyi A. The beta adrenergic theory of the atopic abnormality in bronchial asthma. J. Allergy 42:203-232, 1968.) DHEA, DHEAS, and the estrogens, estadiol and estriol, were lower in the women with AdBCs compared to a group of women without AdBCs.
The diminished levels of serum DHEAS in the subjects with asthma can be corrected by the administration of an adrenergic stimulant, albuteral. The mode of action for albuteral is substantially similar to the mode of action for other adrenergic stimulants. Therefore, researchers have concluded that the decrease in DHEA, DHEAS and estrogens results from diminished adrenergic responsiveness which occurs in AdBCs.
The diminished adrenergic responsiveness in individuals with AdBCs is specific to the pathway in which the weak androgen DHEA, DHEAS, and estrogens are formed. See FIG. 1. Some steroids in the .DELTA.-4 steroidogenic pathway were not decreased in subjects with AdBCs. For example, 17-OH progesterone and cortisol were found to be normal. Both 17-OH progesterone and cortisol are produced by a pathway which diverges from the one in which DHEA, DHEAS, estradiol and estriol are produced. This suggests that adrenergic blockade affects only the .DELTA.-5 steroidogenic pathway.
DHEA, DHEAS, and Estrogens
DHEA and its sulfated derivative, DHEAS, are major secretory products of the adrenal gland. (Rosenfield R S, Hellman L, Gallagher T F Metabolism and interconversion of dehydroepiandrosterone and dehydroepiandosterone sulphate. J. Endocrinol Metab 35:178-93, 1972.) Levels decrease with age and low levels have been postulated to be predictive of decreased life expectancy and increased mortality from cardiovascular disease. (Orentrich N, Brind J L, Rizer R L, Vogelman J H. Age changes and sex differences in serum dehydroepiandrosterone sulfate concentrations throughout adulthood. J. Clin. Endocrinol Metab 59:551-5, 1984; Barrett-Connor E B, Khaw K, Yen S S C. A prospective study of DHEAS, mortality, and cardiovascular disease. N Engl J Med 315:1519-24, 1986.) DHEA has also been shown to affect immune function. (Hall G M, Perry L A, Spector T D. Depressed levels of dehydroepiandrosterone sulphate in postmenopausal women with rheumatoid arthritis but no relation with axial bone density. Ann Rheum Dis 52:211-214, 1993; Deighton C M, Watson M J, Walker D J. Sex hormones in postmenopausal BLA-identical rheumatoid arthritis discordant siblings. J. Rheumatology 19(11):1663-7, 1992; Tannen R H A and Schwartz A G. Reduced weight gain and delay of Coombs positive hemolytic anemia in NZB mice treated with dehydroepiandrosterone (DHEA). (Abstr.) Fed. Proc. 41:463, 1982; Lucas J., Ahmed S A, Casey L, MacDonald P C. Prevention of autoantibody formation and prolonged survival in New Zealand Black/New Zealand White F1 mice fed dehydroepiandrosterone. J Clin Invest 75:2091-93, 1985; Daynes R A, Dudley, D J, Araneo B A. Regulation of murine lympholine production in vivo. Dehydroepiandrosterone is a natural enhancer of interleukin 2 synthesis by helper T cells. Eur J Immunol 20:793, 1990; Risdon G, Moore T A, Kumar V. Bennett M. Inhibition of murine killer cell differentiation by dehydroepiandrosterone. Blood 78:2387-9, 1991.) Immune function may become disordered with age and aspects of this immune senescence can be ameliorated experimentally by DHEA. (Weksler M E. Immune senescence and adrenal steroids: immune dysregulation and the action of dehydrepiandrosterone (DHEA) in old animals. European Journal of Clinical Pharmacology. 45 suppl. 1:S21-23, 1993; Daynes R A, Araneo B A, Ershler W B, Maloney C, Li GZ, Ryu S Y. Altered regulation of IL-6 production with normal aging. Possible linkage to the age-associated decline in dehydroepiandrosterone and its sulfated derivative. J Immunol 195(12):5219-5230, 1993.)
DHEA, DHEAS, and estrogens also regulate immune function and regulate the elaboration of interleukins which influence the production of allergic antibody, immunoglobin E (IgE). These considerations suggest the benefits of restoring or increasing altered sex steroids in AdBCs.
Decreased levels of DHEA, DHEAS, and estrogens are associated with an increased risk of cardiovascular disease and increased risk of bone loss and osteoporosis. These findings suggest that subjects with severe asthma, especially women, have an increased mortality from ischemic heart disease. (Toren K. Lindholm N B. Do patients with severe asthma run an increased risk from ischemic heart disease? International Journal of Epidemiology 25:617-20, 1996.) These effects can be avoided by supplementation with sex steroids.
Adrenergically Blockaded Conditions
One of the characteristic immune manifestations of adrenergically blockaded conditions (AdBCs) is an overproduction of allergic antibody, immunoglobulin E (IgE). Allergic antibody has the characteristic of attaching to a type of cell located in the skin and in the mucous membranes of the respiratory tract which produces or stores mediators such as histamine. Primed with IgE on their surface, upon exposure to a specific antigen, the agent which the antibody recognizes, these cells release mediators such as histamine and leukotrienes. The release of mediators results in allergic manifestations, (e.g., itching, squeezing and bronchial constriction).
The production of allergic antibody is regulated by interleukins, products of immune cells which regulate the functioning of the cells themselves or the functioning of other immune cells. IgE production is enhanced by interleukin-4 (IL-4) and interleukin-6 (IL-6), and inhibited by another interleukin, gamma-interferon. DHEA experimentally decreases the overproduction of IL-6 in aging and DHEAS enhances production of interleukin-2 (IL-2). (Daynes R A, Araneo B A, Ershler W B, Maloney C, Li GZ, Ryu SY. Altered regulation of IL-6 production with normal aging. Possible linkage to the age-associated decline in dehydroepiandrosterone and its sulfated derivative. (J Immunol 195(12):52:5219-5230 (1993).) IL-2 is known to result in the production of increased gamma-interferon. (Daynes R A, Dudley, D J, Araneo B A. Regulation of murine lymphokine production in vivo. Dehydroepiandrosterone is a natural enhancer of interleukin 2 synthesis by helper T cells. Eur J Immunol 20:793, 1990.) Therefore, finding of diminished levels of DHEA and DHEAS in individuals with atopy consequent to adrenergic blockade provides a link to correcting allergic antibody overproduction in AdBCs by correcting the depletion of DHEA and DHEAS.
Pathogenesis of osteoporosis is multifactorial, factors being activity and weight bearing. Inactivity and use of cortisone-like medication are usually considered factors in osteoporosis related to AdBCs. (Ip M, Lam K, Yam L, Kung A, Ng M. Decreased bone mineral density in premenopausal asthma patients receiving long-term inhaled steroids. Chest 105:1722-7, 1994; Eisman JA. Pathogenesis of Osteoporosis In Rheumatology. Klippel J A, Dieppe P A (eds.) pp. 33.1-33.6, St. Louis, 1994 Mosby.)
We now know that another consideration, adrenergic blockade and diminished hormone synthesis are likely contributing factors. The recent finding that DHEA, DHEAS and estrogens are decreased in AdBCs is likely to be another cause of bone depletion and osteoporosis. Moreover, it is known that depletion of DHEA, DHEAS and estrogens increases bone reabsorption and osteoporosis. These effects can be improved experimentally by DHEA supplementation. (Daynes R A, Araneo B A, Ershler W B, Maloney C, Li GZ, Ryu S Y. Altered regulation of IL-6 production with normal aging. Possible linkage to the age-associated decline in dehydroepiandrosterone and its sulfated derivative. J Immunol 195(12):52:5219-5230, 1993; Jilka R L, Hangoc G I, Girasole G, Passari G, Williams D C, Abrams J S, Boyce B, Broxmeyer H, Manolagas S C. Increased osteoclast development after estrogen loss: Mediation by interleukin-6. Science 257:88-91, 1992.)